Wooster Geologists

Mark Wilson March 21st, 2019

During our 2019 Spring Break, Dr. Shelley Judge, our ace technician Nick Wiesenberg, and I took two students (Anna Cooke ’20 and Evan Shadbolt ’20) to southwestern Utah for Independent Study (IS) research and geologic exploration. We had a great time, and as always we’re planning the next expedition. Anna and Evan collected nearly a hundred pounds of rocks from the Middle Jurassic Carmel Formation for their IS projects. Here are links to our daily blog posts in classic superpositional order (youngest on top):

March 20: Local culture on our last day in Utah
March 19: A free day spent geologically in southwestern Utah
March 18: Wooster Geologists return to Zion National Park
March 17: Last day of fieldwork for Team Jurassic Utah 2019
March 16: East of Zion
March 15: Fieldwork continues for Team Jurassic Utah, plus a museum visit
March 14: A much more pleasant day in southwestern Utah
March 13: Team Jurassic Utah endures polar conditions
March 12: A productive first day for Wooster Geologists in Utah
March 11: Team Jurassic Utah 2019 begins its adventure

(You can also search the tag “Utah2019”.)

This is the local stratigraphic column (modified from that on the Zion National Park website). The area is dominated by the magnificent Navajo Sandstone. The Carmel Formation (red dot) is one of the few carbonate units.

This expedition builds on the work of last year’s Team Jurassic Utah, Galen Schwartzberg ’19 and Ethan Killian ’19, along with a past generation of Wooster students in the 1990s. We thank them for their contributions to this continuing geological adventure. Thank you also to Patrice Reeder, our Administrative Coordinator, for all her help. Our colleague lab technician Nick Wiesenberg was a superb trip organizer, driver and field geologist. We are also grateful to the very generous landowners Hyrum & Gail Smith and Jay & Judy Leavitt.

Updates on our progress with these projects will be in future blog entries.

For our records, here are our collecting and measuring localities —

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Mark Wilson March 20th, 2019

Hurricane, Utah — On our last day in Utah, we packed up and shipped our samples back to Wooster by FedEx (almost 100 pounds of rock) and then visited the St. George Temple of The Church of Jesus Christ of Latter-Day Saints (the Mormons). I find Mormon history and theology fascinating, and the visitor center at the never disappoints.

You can see from the background sky that it was a cool, overcast day. Perfect for packing up and getting our equipment and notes together.

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Mark Wilson March 19th, 2019

Hurricane, Utah — Team Jurassic Utah finished its fieldwork two days ahead of schedule because I hadn’t calculated just how efficient it is to have Dr. Shelley Judge as a member. Twice as fast, twice as good. We thus were able to have yesterday in Zion National Park and today in the St. George area. With the perfect weather this was the place to be an exploratory geologist.

We first drove down a long dirt road to a site in Warner Valley which has exposed Lower Jurassic dinosaur tracks.

Here I’m photographing the best theropod dinosaur track with Anna’s help. (Image by Nick Wiesenberg.)

Here’s the nice footprint. Notice how the mud was squeezed up between the toes as the theropod sloshed its way across a floodplain. This shape of dinosaur track is given the trace fossil name Eubrontes.

The footprint layer in Warner Valley is in the lower part of the Kayenta Formation (Lower Jurassic).

We next visited a beautiful neighborhood in Bloomington which has in its midst an excellent set of Indian petroglyphs. The Bloomington Petroglyph Park is tiny, but well worth the drive.

Anna is here photographing the largest surface of petroglyphs.

Most of the petroglyphs were made by carefully scraping away a layer of desert varnish on light-colored sandstone blocks. Humans and animals are easily recognizable; other symbols are mysterious.

After lunch we went to the Dino Cliffs site in the Red Cliffs Desert Reserve. We had a nice hike through exposures of the Kayenta Formation. (The top image of this post is also from this area.) We found the dinosaur tracks, but their poor preservation did not merit a photo.

Finally we went to the old 19th century mining town of Silver Reef. The museum was closed, but we were able to walk around the old buildings still preserved, along with antique mining equipment on display.

Most of the old town is long gone, leaving some evocative ruins.

The wildflowers today were uncommon. They included the classic Indian Paintbrush (Castilleja angustifolia) …

… and significant numbers of Spectacle Pod (Dimorphocarpa wislizeni). Thank you to my Mother Corinne Wilson for the identification!

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Mark Wilson March 18th, 2019

Hurricane, Utah — With our fieldwork done, Team Jurassic Utah 2019 visited Zion National Park today. The weather could not have been better. The students and Nick climbed Angels Landing (a rite of passage!) and entered The Narrows, so they saw the park from top to bottom. Above are Anna and Evan with our flag and surrounded by the iconic Navajo Sandstone. Nick took this photo.

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Mark Wilson March 17th, 2019

Hurricane, Utah — Our expedition had its final official fieldwork today, which we marked with a group photo overlooking the magnificent Snow Canyon. See the end of this post for alternative flag group images!

Tomorrow the group visits Zion National Park. The next day will be spent exploring the local geology and culture, and then it is packing up our samples for shipment to Wooster. Today, though, The Carmel Formation calls one last time!

We returned to the extensive Carmel outcrops in Dammeron Valley, looking at the northernmost extension of the ooid shoal facies. Here is our short shoal section at Dammeron Valley North (DVN), which consists entirely of cross-bedded limestones placed in four subunits (A-D).

This exposure weathered into many loose slabs from the upper subunit D. The trace fossils are well preserved, including this Planolites with rare branching. It is convex hyporelief.

The traces here include a sinuous bilobed Gyrochorte and a thick trace in the left foreground I can’t yet identify. Anna found this rippled slab.

This big trace Evan found is almost certainly Rhizocorallium.

We originally thought that our section today (DVN) was an extension 638 meters to the west of the DV shoal unit. Nick and Shelley did excellent stratigraphic detective work to show that DVN is about 15 meters below the DV measured unit. We thus found the eastern equivalent of DVN at the DV location, measured and sampled it. For now we call it “DVN at DV”. More detail than anyone wants to know, but these blog entries are also a kind of field notes!

The traditional Wooster flag group photo as taken by Shelley.

The flag group photo taken by Nick.

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Mark Wilson March 16th, 2019

Hurricane, Utah — Today Team Jurassic Utah traveled to Mt. Carmel Junction, east of Zion National Park, to examine the extensive outcrops of the Carmel Formation in the region. The most famous location is in Mt. Carmel Junction itself (MCJ: N 37.22521°, W 112.68095°). It is this crinoid-rich limestone that is reported to be the youngest encrinite in the geological record.

Anna and I measured a two-meter column in this unit to collect samples for thin-section analysis. Four subunits (A-D) start at the bottom of the ruler here.

This is the base of subunit D. It is full of the star-shaped columnals of the crinoid Isocrinus nicoleti. It is one of only three Jurassic crinoid species in North America.

Fieldwork! Love it. Photo by Nick.

Shelley again measured cross-beds to determine current directions here. This was a complicated task because at least three joint sets intersect in these rocks.

Lunch along the Virgin River. Photo by Nick.

After lunch we went just a bit south of Mt. Carmel Junction to examine a Carmel Formation outcrop that looked superficially like it would be identical to the previous unit. We call the place Carmel Cove (CC: N 37.21548°, W 112.68215°). Turns out the limestone here is very different: no crinoids, no ooids, and relatively abundant bivalves. Amazing variability in sections within sight of each other.

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Mark Wilson March 15th, 2019

Hurricane, Utah — Every day is a little warmer. Today the team worked on a long section of the Carmel Formation in Dammeron Valley (locality DV: N 37.27629°, W 113.63712°). It is a complete section oof the Co-Op Creek Limestone Member, from its lower contact with the Temple Cap Formation to its upper contact with the Crystal Creek Member.

Our objective was to find the same oolitic unit we measured and sampled at the Water Tank Road (WTR) locality yesterday. We want to see what facies differences are evident within an ooid shoal over some distance. We found the unit with the help of “Nick’s Sandstone” present as a marker bed about five meters above. The unit is shown above. It still has four parts (A-D), but the A unit at the base has a significant siliciclastic component. This Dammeron Valley (DV) unit is also about half as thick as that at WTR. The DV section is 3.74 km north of the one at WTR.

Shelley explored the unit and found very faint bedding structures, a mix of wave and current ripples. She and Anna again collected data to ascertain current and wave directions.

Shelley and Anna are here measuring current and wave directions. Photo by Nick.

Here is Evan in his field mode. My photo of him yesterday was faceless.

This is the top of the Temple Cap Formation in Dammeron Valley. The Carmel is immediately above. Here you can see the distinctive red siltstones and an interval of gypsum beds at the very top.

It was our pleasure to briefly visit the St. George Dinosaur Discovery site today. This is a fantastic museum and laboratory built over bedding planes of the Moenave Formation (Lower Jurassic) covered with dinosaur tracks and sedimentary structures.

The sediments formed along a shoreline of ancient Lake Dixie, so there is a diverse mix of terretrial and aquatic features.

We mainly wanted to visit with Andrew Milner (on the left), the site paleontologist and curator. He always has good paleontological stories and advice. Today he showed us a tiny but significant ammonite found in the Carmel at the Eagle Mountain Ranch locality. We also looked at various vertebrate fossils being prepared in his lab.

Finally, we need to show our beautiful headquarters for this trip — an Air BnB in Hurricane. Since camping is not possible for us, this turned out to be a surprisingly affordable housing option. The garage alone is a bonus for organizing samples and equipment. We are plenty comfortable here!

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Mark Wilson March 14th, 2019

Hurricane, Utah — This is our morning view to the north from our Team Utah headquarters in Hurricane. The snowy Pine Valley Mountains were especially beautiful as the clouds lifted overnight. Such colors. A much warmer day was ahead of us after our freeze-fest yesterday.

Today we returned to the Water Tank location we briefly visited yesterday. This time we concentrated on this meter-thick set of cross-bedded oolites. We described this little column, took four samples, and named the location WTR (for “water tank road”). The coordinates are: N 37.25500°, W 113.60436°.

Anna is here examining the top of the sequence, which appears to represent an ooid shoal.

A very covered Evan does the same. Today he is not protecting himself from the cold as much as the sun.

Dr. Judge, with Anna’s help, collected measurements of the cross-beds to eventually calculate current flow direction, which will be very interesting.

While on a scouting trip for the team, Nick found this mysterious quartzose sandstone unit 5.4 meters above the WRT oolite. It is very much an oddity in an otherwise carbonate sequence. In some parts the sand is loose enough to later run through the Ro-Tap sieves.

For lunch we went to a favorite Wooster restaurant — Veyo Pies! Very appropriate (and crowded) on Pi Day. Photo by Shelley.

Every time I visit this region I make a pilgrimage to the 1857 Mountain Meadows Massacre site north of Central, Utah, on Highway 18. Today it was snow-covered, which made the place seem even lonelier. Please read the historical account of what happened here.

The rock cairn over the mass grave. Lest we forget.

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Mark Wilson March 13th, 2019

Hurricane, Utah — Well, maybe not fully polar, but it was very cold and windy in southern Utah today. Our glove-less fingers were numb, and the bitter gusts penetrated our pitiful parkas. We collected some samples but put off measuring columns (which inevitably requires working fingers) for a warmer day.

Our mission, as before, was to find ooid-rich units for Anna and mollusk fossils for Evan. We were at the “Water Tank” locality (C/W-751) of last year. It is our least attractive site, having a blue water tower and all.

The bivalves here are numerous and diverse, but only in a narrow horizon (so far). They are certainly more species-rich than at yesterday’s Eagle Mountain Ranch site.Anna found a cross-bedded ooid-rich limestone along the road to the water tank. We will be back to measure and sample this section in detail.For lunch we went to nearby Snow Canyon State Park, where we hoped it would be a tad warmer. (It was — barely.) The sun was out and the colors vivid. This is the Petrified Dunes walk. All you see here is the glorious Navajo Sandstone (Jurassic — beneath the Temple Cap and Carmel Formations).I was entranced by the Moqui Marbles, a kind of iron oxide concretion that weathers out of the Navajo Sandstone. They accumulate in large numbers on the flat surfaces here.

Nick with Moqui Marbles eroded out of the Navajo.Here are Moqui Marbles in place in cross-beds of the Navajo. (Guess whose legs are the scale.) These concretions are diagenetic, forming in the sandstone long after deposition. You can read the latest ideas on their formation in this Moqui Marbles article.

The cold, cold group in Snow Canyon. Image by Shelley.

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Mark Wilson March 12th, 2019

Hurricane, Utah — Team Jurassic Utah 2019 started its fieldwork on a cloudy March day with a bit of a chill and some light rain, but it didn’t rain again and the cooler temperatures were comfortable. We worked on the Eagle Mountain Ranch site (C/W-142) looking for ooids (Anna’s Independent Study project) and mollusks (Evan’s I.S. work). Thank you again to ranch owners Hyrum and Gail Smith for permission to work on this important outcrop. (Photo by Nick Wiesenberg.)

Anna and Evan are here describing a critical meter-thick resistant limestone in an otherwise clay-dominated portion of the Co-Op Creek Limestone Member of the Carmel Formation. We think it represents a normal marine incursion into an otherwise restricted lagoonal environment. This is where most of the fossils and ooids at Location C/W-142 come from.

The base of the unit has these very nice wave ripples indicating shallow water.

Nick and Shelley did excellent work measuring the 39 meters of our Carmel interval. They used a Jacob’s Staff with a Brunton compass attached to account for the rock attitude (strike and dip).

Shelley and Nick are the colored dots at the top of our Eagle Mountain Ranch section. They sampled the top of the Carmel here, finding it to be a brecciated limestone below an unconformity with the overlying Upper Cretaceous Iron Springs Formation. The grey wedge of rock thickening to the left is a mysterious claystone. With the breccia discover, we at least know it is above the Carmel.

The team at lunch overlooking the Eagle Mountain Ranch. The slope seemed much steeper than this! (Photo by Nick.)

I know it doesn’t look like much, but Evan found this internal mold of an ammonite at C/W-142. It is the first I’ve seen in the Carmel. (Later Andrew Milner will show us another ammonite from the same location.)

This is the venter view. Definite ammonite, but unidentifiable beyond this!

On the walk back from our main locality, we examined a laminated micritic part of the Co-Op Creek Limestone Member (Location Strom-mat at N 37.30882°, W 113.73883°). This is just below our main section of interest. (Photo by Nick.)

Anna is photographing close details of this unit.

The laminations are spectacular, apparently representing microbial mats. Another future Independent Study project!

Finally, on our drive back to Hurricane we checked out our access to the classic oyster ball localities on the west side of the Santa Clara River. Here is an image of the bridge last year.

The bridge today! A flood destroyed it last month. No way we’re crossing here. Time to explore other options.

Team Jurassic Utah at the Gunlock Reservoir, with the fantastic Carmel Formation in the background.

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